Just some clarification for any new shamans. From day one the wording on the spell info has been very wrong. It's not everything in a small radius around the target. There are 2 limits, 3 waves or 4 total hits, which ever is first.
So you will only get 3 waves if there is only one mob. If you have 2 mobs each mob will take 2 hits for 4 total and there will be no 3rd wave. If you have 3 mobs each mob will take 1 hit then one and only one mob will take a hit from a second wave for 4 total and that will be it. If you 4 or more mobs only the 1 targeted mob and 3 other random ones will take 1 hit of dmg and there will be no second wave.